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T Kasuga

Publications and source records attributed to T Kasuga.

At least 91 records · Page 5Linked to original sources
PubMed1991

Development of a high-resolution digital tomosynthesis system and its clinical application.

Conventional tomography has been criticized for its low contrast caused by scattered radiation and tomographic blur. The authors developed a digital tomosynthesis system as a substitute for conventional tomography. With the image processor in the system, two types of postprocessing can be performed to improve the quality of synthesized tomograms. One-dimensional spatial frequency filtering effectively reduces linear tomographic blur and enhances image information when an appropriate filter is used. Correction of structure mottle helps enhance the image clarity. The system allows reconstruction of tomograms at any desired depth and performance of tomosynthetic angiography and dual-energy subtraction. The system solves some of the problems associated with plain tomography and dual-energy subtraction and provides diagnostic clinical images.

Humans↗
PubMed1991

Digital image processing to remove blur from linear tomography of the lung.

We have studied digital image processing methods to reduce blur in linear tomography of the lung performed with the Fuji computed radiography (FCR) system. One-dimensional unsharp (blur) mask filtering in the direction of tomographic movement was found to be effective in reducing blur. The appearance of the processed tomograms varied depending largely on the properties of the unsharp mask filters applied. With regard to the spatial frequency response of the filter, a high mid-frequency response and a low low-frequency response of the tomographic image data was most effective in obtaining high image quality tomograms. When the standard 2-dimensional unsharp mask technique of the FCR system was additionally applied to the one-dimensional unsharp mask processed tomogram, the clarity of the tomogram was further enhanced. These observations may also be helpful when considering image processing to obtain diagnostically informative digital radiography.

Humans↗
PubMed1990

Responses of a murine B16 melanoma to pharmacotherapy studied and compared with different assay systems.

The responses of B16 melanoma in C57BL mice to cytotoxic agents, cyclophosphamide, doxorubicin, and dactinomycin, were studied by different methods both in vivo and in vitro. Either treated tumors were allowed to grow in vivo or cells were isolated and cultured in vitro afterwards. The tumor cells were also treated in vitro and assayed in vitro. For cyclophosphamide, a fairly good correlation was found among the dose responses measured: the tumor growth delay, incidence of giant cells, decrease in mitotic index, clonogenic cell survival of tumor cells treated in vivo and the survival of cells treated in vitro. For doxorubicin and dactinomycin, on the other hand, the tumor growth delay was not marked, the appearance of giant cells and decrease in mitotic index were minimal, and almost no decrease was found in the clonogenic cell survival for tumor treated in vivo, although the cells responded well to in vitro exposure. The results indicate substantial differences in the expression of damage according to the conditions of tumor cell growth and assay after treatment with different agents.

Animals↗
PubMed1990

Melanocytes and melanosis of the oesophagus in Japanese subjects--analysis of factors effecting their increase.

Normal oesophagus specimens taken from 65 autopsy cases and surgical specimens from 127 oesophageal carcinoma cases were examined histopathologically to determine melanocyte incidence and distribution. Melanocytes were found in the epithelio-stromal junction in 7.7% of normal oesophagus specimens examined at autopsy, and in 29.9% of surgical cases with oesophageal carcinoma. Positive specimens in the latter groups, especially from pre-operatively irradiated individuals, showed a more remarkable increase of melanocytes than was evident in any of the normal oesophageal samples. There were no significant differences in incidence between males and females, or between age groups. In cases where the cancer invaded into deeper stroma, the melanocytes were mainly observed in the normal epithelium around the carcinomas. Epithelial and stromal elements of the melanotic mucosa commonly showed hyperplastic changes such as acanthosis or basal cell hyperplasia, and chronic oesophagitis. Melanocytes were observed most commonly in the lower part of the oesophagus, the site where malignant melanoma of the oesophagus, most often originates. These results strongly suggest that the melanocyte increase observed in areas of hyperplastic epithelium and chronic oesophagitis may play an important role as a precursor lesion for malignant melanoma in the oesophagus.

Asian People↗
PubMed1990

In vivo dynamics of pulmonary lymphoid cell subpopulations generated against pulmonary metastasis: evaluation by bronchoalveolar lavage fluid.

The dynamics of lymphoid cell subpopulations in bronchoalveolar lavage fluid (BALF) and the systemic lymphoid organs of mice after intravenous injection of B16 melanoma cells were examined with a fluorescence-activated cell sorter. The lymphoid cell subpopulations of BALF and mediastinal lymph nodes showed significant changes in numbers and proportions, while those of other lymphoid organs including inguinal lymph nodes, thymus and spleen, showed little change. In week 1, the cells with a Thy-1.2+, Lyt-1+, L3T4-, Lyt-2- phenotype and asialo-Gm1+ cells in BALF significantly increased and L3T4+ cells slightly increased in number. By week 3, the numbers of Lyt-2+ cells in BALF markedly increased in number (by about 90 times) compared with controls. The number of Thy-1.2+ cells in mediastinal lymph nodes also increased significantly by week 3. Mice that had been pretreated with an immunosuppressive dose of cyclophosphamide were also inoculated intravenously with B16 melanoma cells. In these mice, a significantly increased number of pleural tumors developed and the number of Thy-1.2+ cells in BALF was markedly reduced from week 1 to 3. The results indicate that L3T4 and Lyt-2 double negative T-cells and natural killer (NK) cells may be generated and/or mobilized to the lung in an early phase of experimental metastasis of B16 melanoma cells and that at a later stage, when multiple metastases develop, T-cells with a Lyt-2+ phenotype markedly increase, probably as an expression of a host reaction against proliferating metastatic tumor cells.

Animals↗
PubMed1990

The effect of L-dopa on the potentiation of radiation damage to human melanoma cells.

Since L-dopa (L-3,4-dihydroxyphenylalanine) has been shown to possess a selective toxicity for melanoma cells both in vitro and in vivo, we have examined the combined effect of L-dopa and radiation on human melanoma cells. It was found that the combined use of L-dopa potentiated the radiation cytotoxicity to HMV-I human melanoma cells, compared with the response seen in non-melanoma HeLa S3 cells. In HMV-I cells during their exponential phase, L-dopa decreased the shoulder width of the radiation survival curve significantly. In addition, L-dopa significantly inhibited the repair of potentially lethal damage (PLD) in HMV-I cells during their plateau phase. When the distributions of the G1, S, and G2-M cells were measured 24 h after combined L-dopa and radiation treatment, there was significant increase in the accumulation of cells in the G2-M phase of the cell cycle, compared to cells that received either L-dopa or radiation treatment only.

Cell Cycle↗
PubMed1990

Localization of 90-kDa heat shock protein in the kidney.

Antibody against 90-kDa heat shock protein (HSP 90) was produced in rabbits. The obtained antibody was highly specific to the antigen. Using the antibody, the intrarenal distribution of HSP 90 was studied in frozen sections of normal rat kidneys by fluorescent and enzymic immunohistochemistry. HSP 90 was predominantly present in the region from the distal convoluted tubule to the medullary collecting duct at a high intensity, and in glomerular podocytes and Bowman epithelial cells at a much lower intensity. Other segments of the nephron were stained little, even at a lower dilution of the antibody. Blood vessels and interstitial tissues were not stained. HSP 90 was localized in the cytoplasm and not in the nucleus. Moreover, immunohistochemical staining of HSP 90 showed greater intensity at the luminal side of the cells. These observations suggest that HSP 90 might play important roles in the kidney.

Animals↗
PubMed1990

High resolution ultrasound of the chest wall.

To study the detailed normal ultrasonic anatomy of the pleura and chest wall, high resolution (7.5 MHz) ultrasonograms were obtained from cadaver chest wall specimens and compared with thin section computed tomograms and anatomical specimens. Ultrasonograms show three layers of the intercostal muscles (internal, external and innermost), covered by the "echogenic pleural line." The "echogenic pleural line" is caused by composite echoes from the inner parietal pleura, and the outer endothoracic fascia, with the fatty tissue covering both sides of the fascia, which are located deep to the chest wall muscles. On ultrasonograms, the subpleural fat tissue, when abundant, appeared as an apron-like structure hanging down from the inner surface of the rib (subpleural fat pad), or diffuse fat accumulation mimicking the pleural thickening.

Humans↗
PubMed1990

Clonal heterogeneity of a human functioning tumor which produces granulocyte colony-stimulating factor.

Two different clonal strains have been isolated from a human squamous cell carcinoma which produces granulocyte colony-stimulating factor (G-CSF). The clones differed in morphology, growth characteristics, karyotype, production of G-CSF, histology of the tumors produced by inoculating the cultured cells, and in the development of granulocytosis in host mice transplanted with the cultured cells. A well-differentiated squamous cell carcinoma was developed by inoculation with clone 1 cells into athymic nude mice. No CSF activity was detected in the cultured medium of the cells. The host mice with the transplanted cells showed no increase in peripheral blood neutrophils. Clone 2, which formed a poorly-differentiated squamous cell carcinoma in nude mice, produced a large amount of CSF in vitro and developed a marked neutrophilia in host nude mice. Clone 1 cells were more sensitive to bleomycin than were clone 2 cells in vitro. The results suggested the G-CSF producing tumor to be heterologous and the cells with different functional properties, including G-CSF production, sensitivity to bleomycin, and keratinization, to pre-exist in the parental cell population.

Animals↗
PubMed1990

Portal vein resection with a new antithrombogenic catheter.

Curative resection of pancreatic and hepatobiliary tumors is rarely possible because of local invasion, especially into the portal vein. We developed a new antithrombogenic catheter using a heparinized hydrophilic polymer to allow portal vein bypass during resection of tumors invading the portal vein. Pancreatectomy or hepatectomy accompanied by portal vein resection was performed for pancreatic or hepatobiliary cancer, with an intraoperative shunt from the superior mesenteric vein to the femoral vein or from the superior mesenteric vein to the intrahepatic portal vein through the umbilical vein or the hepatic hilar portal vein. Use of the shunt prevented stasis in the superior mesenteric vein and hepatic ischemia even during prolonged occlusion of the portal vein, and portal vein resection was performed in 81 patients with hepatobiliary and pancreatic disease with greater safety and ease.

Anastomosis, Surgical↗
PubMed1990

Long-term follow-up study of children developmentally retarded by early environmental deprivation.

In 1972, two children representing a case of severe developmental retardation were discovered and taken into custody. The children, an older sister (referred to as F) and a younger brother (referred to as G), were found to have achieved no more than the physical and mental age level normal to children 1 year of age or less, in spite of their actual respective chronological ages of 6 and 5. Investigation revealed that the children's developmental retardation was due both to extreme social isolation and to complex deprivation. By following their sensorimotor, linguistic, cognitive, and socio-emotional development from the time of discovery to the date of this writing, we have found that their physical and motor development or recovery has proceeded smoothly, whereas their linguistic and cognitive development has continued to show such weaknesses as defective functioning of internal speech (Vygotsky, 1962) and poor ability to deal with abstract, linguistic subjects. F and G have continued to exhibit a tendency toward undersocialization, but this has at times been rather a positive factor in the process of attaining ego identity during adolescence, especially for G, serving to protect him from unreasonable social pressures to conform to group behavior. In combination with other cases of severe deprivation, the case of F and G holds some interesting implications for theories of human development, particularly the notion of critical periods.

Child↗
PubMed1989

[N-isopropyl I-123 p-iodoamphetamine single photon emission computed tomography of herpes simplex encephalitis].

Two patients with herpes simplex encephalitis were studied with N-Isopropyl I-123 p-Iodoamphetamine (IMP) single photon emission computed tomography (IMP-SPECT) and X-ray computed tomography (CT). In both cases the affected temporal lobes showed an increased IMP uptake. In case 1, the initial increased IMP uptake decreased as symptoms and CT findings improved. In case 2, the increased IMP uptake was shown at the time of symptoms progressed, while CT had no abnormal findings. IMP uptake is sensitive for its demonstration of inflammatory processes of herpes simplex encephalitis.

Aged↗
PubMed1989

Bone marrow analysis of the myelodysplastic syndromes: histological and immunohistochemical features related to the evolution of overt leukemia.

Bone marrow trephines from 31 patients with an initial diagnosis of myelodysplastic syndromes (MDS) were examined and analyzed histologically and immunohistochemically. In those cases terminating in overt leukemia (6/31, 19%), the number of bone marrow mast cells was significantly reduced, compared with those which did not evolve to overt leukemia. The bone marrow lymphoid cells that may participate in immunosurveillance against the proliferation of blast cells were also significantly reduced in cases terminating in overt leukemia. However, S-100 protein-positive cells, which include histiocytes and suppressor T-cells, were increased in cases terminating in overt leukemia. The results indicated that examination of the bone marrow to determine the proportions of mast cells and lymphoid cells which may be involved in host defense systems may be useful in predicting the evolution to overt leukemia in MDS. In the present series, patients with a hypocellular marrow (5/31, 16%) did not progress to overt leukemia and had a significantly lower bone marrow reticulin content, a significantly lower megakaryocyte count, a relatively higher mast cell count and a significantly higher lymphoid cell count than those with a normocellular or hypercellular marrow. These findings may reflect the initial features of MDS or, possibly, that hypocellular MDS is an independent entity with a low potential for blastic proliferation.

Aged↗
PubMed1989

Transplacental induction of peripheral nervous tumor in the Syrian golden hamster by N-nitroso-N-ethylurea. A new animal model for von Recklinghausen's neurofibromatosis.

Multiple peripheral nervous tumors were induced in 45 of 60 (75.0%) Syrian golden hamsters by transplacental administration of N-ethyl-N-nitro-sourea. Moreover, melanomas, pheochromocytomas, and Wilms' tumors developed in six (10.0%), three (5.0%), and 13 (21.7%) animals, respectively. The histologic, immunohistochemical, and electron microscopic findings of the peripheral nervous tumors were similar to those of human neurofibroma, and their growth pattern and distribution resembled those of human von Recklinghausen's neurofibromatosis (VRNF). The occurrence of melanoma, pheochromocytoma, and proliferative foci of melanin-containing cells in neurofibroma suggests that the targets of ENU in hamsters are the neural crest-derived cells. With its high incidence of Wilms' tumor, the hamster with ENU-induced tumors is considered to be a good animal model for human neurocristopathy, including VRNF.

Animals↗
PubMed1989

[Quantification of severity and redistribution of ischemic and infarcted myocardium by Thallium-201 polar map: evaluation in patients with single vessel disease].

Quantitative analysis of the polar map obtained from T1-201 single photon emission computed tomogram was employed to assess regional myocardial viability in 66 patients with single vessel coronary artery disease and 16 control subjects. Counts of region of interest in the stenotic and infarcted lesions and normal reference areas were calculated on the polar map. Severity of hypoperfused myocardium was determined as initial percent uptake (%Ui) and delayed percent uptake (%Ud). Redistribution was analyzed as a ratio of %Ud to %Ui (%Ud/%Ui). In the control group, the average %Ui was 85.8 +/- 9.4 and %Ud/%Ui was 1.03 +/- 0.04. Twenty five with reversible defect showed reduced %Ui (51.5 +/- 13.3) and increased %Ud/%Ui (1.37 +/- 0.26). Forty one cases with non-reversible defect were divided into two groups according to the value of %Ui. In the first group with a high %Ui (n = 17), the average %Ui was 74.5 +/- 4.7 and %Ud/Ui was in normal range (1.06 +/- 0.06). In the second group (n = 24), %Ui was most reduced (31.7 +/- 8.7), although %Ud/%Ui was in normal range (1.05 +/- 0.17). No significant correlation was shown between %Ui and %Ud/%Ui in the two groups with non-reversible defect. Correlation between %Ui and %Ud/%Ui was high (r = -0.76) in the group of reversible defect and the group of non-reversible defect with minimal reduced %Ui. It is concluded that the quantitative criteria obtained from polar map is valid to assess regional myocardial viability. The quantitative imaging data were also compared with coronary angiographic and left ventriculographic data.

Aged↗
PubMed1989

Pulmonary thromboembolism: frequency, site, and vascular change in 103 autopsy cases.

For investigation of the incidence of pulmonary thromboembolism, the sites of thromboemboli, pulmonary vascular changes, detailed clinical and autopsy records, and histological sections of a series of 103 autopsied adults were reviewed. Pulmonary thromboembolism was observed in 38.8% of these cases. Pulmonary thromboembolism tended to be more frequent in older, younger, female, and cancer patients. Thromboembolism was found most frequently in arterioles, followed by muscular arteries. A significant correlation (P less than 0.02) was found between the incidence of pulmonary thromboembolism and the histological changes of endothelial protrusion and vacuolization of the intima in these small pulmonary arteries, but no correlation was found between that of pulmonary thromboembolism and constriction figures. These endothelial changes probably represent previous vasoconstriction. The present observations suggest a significant relationship between pulmonary thromboembolism and vasoconstriction of small pulmonary arteries and suggest that widespread vasoconstriction of pulmonary arteries is important in the pathogenesis and pathophysiology of this condition.

Adolescent↗
PubMed1989

[A case of marked exercise-induced ST segment depression in anterior precordial leads with inferoposterior left ventricular aneurysm and significant stenosis of left anterior descending artery].

A 71-year-old man was admitted to a community hospital and diagnosed as having acute infero-posterior myocardial infarction. Severe ST segment depression occurred in anterior precordial leads with only 50 m walking, but he had no chest pain. He was then admitted to our hospital. Left ventriculography showed infero-posterior dyskinesis and aneurysm formation. Coronary angiography revealed triple-vessel disease including 90% stenosis at distal site of left anterior descending artery. Exercise thallium-201 myocardial scintigraphy by ergometer showed no filling defect in the anterior segment, though severe ST depression appeared in anterior precordial ECG leads. Infero-posterior segment showed persistent defect. We performed intravenous digital ventriculography at rest and during atrial pacing. Anterior wall motion during pacing was shown to be normal by amplitude and phase analysis. At the same time, the motion of the inferior wall was seen as abnormal and ST segment depression on anterior precordial leads appeared. We considered that in this case the anterior ST depression did not mean anterior myocardial ischemia but might be due to dyskinetic movement of the infero-posterior aneurysm.

Aged↗